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3 years ago

Ethan had 81 CDs until he won c more in a contest. Choose the expression that shows how many CDs Ethan has now.

1 answer:

7 0

Add the 81 CDs Ethan had at first and add the number c he won at the contest to get the total number of CDs after the contest.
Making b the correct answer

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Use substitution to solve the following system of linear equations and fill in the following blanks:

marissa [1.9K]

Answer:

$x=-4$

$y=3$

$z=-5$

Step-by-step explanation:

Given:

$x+y+z=-6$

$x-6y-7z=-29$

$-7y-5z=4$

Solve for $x$ in the 1st equation:

$x+y+z=-6$

$x+y=-z-6$

$x=-y-z-6$

Substitute the value of $x$ into the 2nd equation and solve for $z$ :

$x-6y-7z=-29$

$(-y-z-6)-6y-7=-29$

$-7y-z-13=-29$

$-7y-z=-16$

$-z=-16+7y$

$z=16-7y$

Substitute the value of $z$ into the 3rd equation and solve for $y$ :

$-7y-5z=4$

$-7y-5(16-7y)=4$

$-7y-80+35y=4$

$28y-80=4$

$28y=84$

$y=3$

Plug $y=3$ into the solved expression for $z$ and evaluate to solve for $z$ :

$z=16-7(3)$

$z=16-21$

$z=-5$

Plug $z=-5$ into the solved expression for $x$ and evaluate to solve for $x$ :

$x=-(3)-(-5)-6$

$x=-3+5-6$

$x=2-6$

$x=-4$

Therefore:

$x=-4$

$y=3$

$z=-5$

6 0

3 years ago

Given f(x)=4X+9, find the equation for f^-1(x)

Ilia_Sergeevich [38]

Answer:

4x+9 if that's not what u needed I can graph it for you too

6 0

3 years ago

Solve for w in P = 2w + 2l, if P = 38 and l = 12.

vova2212 [387]

W= 7

38=2w+2(12)
/
38=2w + 24
-24 -24

14=2w
divid by 2 divid by 2

7=w

4 0

4 years ago

Read 2 more answers

Write an expression to represent the product of 6 and the square of a number plus 15.

inn [45]

Answer:

6x² + 15

Step-by-step explanation:

Let the number be x.

"the square of a number"

x²

"the product of 6 and the square of a number"

6x²

"the product of 6 and the square of a number plus 15"

6x² + 15

The coefficient is the number that multiplies the variable, so it is 6.

8 0

3 years ago

Please help!

erik [133]

For the answer to the question above,
1 + nx + [n(n-1)/(2-factorial)](x)^2 + [n(n-1)(n-2)/3-factorial] (x)^3

1 + nx + [n(n-1)/(2 x 1)](x)^2 + [n(n-1)(n-2)/3 x 2 x 1] (x)^3 

1 + nx + [n(n-1)/2](x)^2 + [n(n-1)(n-2)/6] (x)^3 

1 + 9x + 36x^2 + 84x^3 

In my experience, up to the x^3 is often adequate to approximate a route. 

(1+x) = 0.98 

x = 0.98 - 1 = -0.02 

Substituting: 

1 + 9(-0.02) + 36(-0.02)^2 + 84(-0.02)^3 

approximation = 0.834 

Checking the real value in your calculator: 

(0.98)^9 = 0.834 

So you have approximated correctly. 

If you want to know how accurate your approximation is, write out the result of each in full: 

1 + 9(-0.02) + 36(-0.02)^2 + 84(-0.02)^3 = 0.833728 

 (0.98)^9 = 0.8337477621 

So it is correct to 4

5 0

3 years ago

Read 2 more answers